ON-CHIP HELIX ANTENNA
A rectangular helix antenna in an integrated circuit includes upper electrodes disposed in a first metal layer, lower electrodes disposed in a second metal layer, and side electrodes connecting the upper electrodes with the lower electrodes, respectively. The upper electrodes are disposed at an angle with respect to the lower electrodes. The upper electrodes, the lower electrodes, and the side electrodes form one continuous electrode spiraling around an inner shape of a rectangular bar. A micro-electromechanical system (MEMS) helix antenna has a similar structure to the rectangular helix antenna, but can have an inner shape of a bar.
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The present disclosure relates generally to an antenna and more particularly an on-chip helix antenna.
BACKGROUNDFor system-on-chip (SOC) applications, on-chip antenna helps integration and keeps the cost down, e.g., for millimeter wave wireless communication, WiFi, and telecommunication, etc. However, for a conventional patch antenna for millimeter wave communication, the performance is an issue with about only 5 dBi gain. Also, the large size of the on-chip patch antenna (e.g., 1.18 mm×0.89 mm for a 77 GHz application) and the antenna cost are problematic. Accordingly, new structures and methods are desired to solve the above problems.
Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
The making and using of various embodiments are discussed in detail below. It should be appreciated, however, that the present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use, and do not limit the scope of the disclosure.
The rectangular helix antenna 100 in an integrated chip includes upper electrodes 102 disposed in a first metal layer, e.g., 126, lower electrodes 104 disposed in a second metal layer, e.g., 118, and side electrodes 106 connecting the upper electrodes 102 with the lower electrodes 104, respectively. In some embodiments, there is at least one metal layer, e.g., 120, 122, or 124, between the first metal layer, e.g., 126, and the second metal layer, e.g., 118.
The upper electrodes 102 are disposed at an angle (α) with respect to the lower electrodes 104. The upper electrodes 102, the lower electrodes 104, and the side electrodes 106 form one continuous electrode spiraling around an inner shape of a rectangular bar. In some embodiments, the side electrodes 106 are vias, e.g., 136, connecting the upper electrodes 102 in the first metal layer, e.g., 126 and the lower electrodes 104 in the second metal layer, e.g., 118
A first ground plane 108 is disposed in a third metal layer, e.g., 128, above the upper electrodes 102 in the first metal layer, e.g., 126. A second ground plane 110 is disposed in a fourth metal layer, e.g., 116, below the lower electrodes 104 in the second metal layer, e.g., 118. The first ground plane 108 and the second ground plane 110 are connected by a vertical ground plane 109 to form a folded grounding. In some embodiments, the folded grounding has an area at least three times of a rectangular area 111 (i.e., the helix area) of the rectangular helix antenna 100, e.g., 4-5 times helix area, as ground. The height (H) between the first ground plane 108 and the second ground plane 110 is 10-17 μm in some embodiments using a Complementary Metal-Oxide-Semiconductor (CMOS) process. The feed line 112 connects the rectangular helix antenna 100 to a transmitter or receiver circuit.
In other embodiments, instead of the folded grounding in
In some embodiments, the rectangular helix antenna 100 is contained in an extended waveguide, e.g., a dielectric layer (e.g., SiO2), as described below in
In the embodiment shown in
The rectangular helix antenna 100 can be implemented using M1 and top metal layer for the first ground plane 108 and the second ground plane 110, respectively. The vertical ground plane 109 can be implemented using vias and/or metal mesh (or by attaching a metal layer during packaging) to form the folded grounding by connecting the first ground plane 108 and the second ground plane 110. The upper electrodes 102 can be implemented using M6, while the lower electrodes 104 can be implemented using M2. The side electrodes 106 can be implemented using vias connecting the upper electrodes 102 and the lower electrodes 104.
The exemplary rectangular helix antenna 100 in
In some embodiments, the rectangular helix antenna 100 has a relatively good bandwidth in that a carrier frequency and the antenna's bandwidth have a ratio of about 2:1, e.g., about 5 GHz bandwidth for a 10 GHz carrier frequency, compared to about 1 GHz bandwidth (10:1) of a patch antenna. The rectangular helix antenna 100 can have a circular polarization depending on the design that provides good reflectivity, less absorption, without a phasing issue of a linear polarization, multiple paths to overcome obstruction, and resistance to weather (e.g., rain or snow).
In one embodiment for a 77 GHz narrow band application, the rectangular helix antenna 100 has an area of about 0.714 mm2, a directivity of 8.52 dBi, and a resolution (3 dB angle in degree) of about 97.8° (this can be improved by better impedance matching), compared to 1.08 mm2, 6.1 dBi, and 180° of a patch antenna. Thus, the rectangular helix antenna 100 provides better performance compared with a patch antenna, and the rectangular helix antenna 100 uses 34% less chip area.
The design and size of a rectangular helix antenna can be determined by the following steps according to some embodiments. First, a single turn of the rectangular helix antenna is calculated to have a length, L of one wavelength (λ) Second, the spacing S between each turn of the helix is selected to have a relationship by the equation: Tan−1(S/L)=12°-14°. Third, the size is fine tuned for the target result. For example if the radiation is not in the desired directional, the spacing S may be too large, and if the gain is too low, the spacing S may be too small. Also, the radiation impedance of the rectangular helix antenna is evaluated to determine which frequency has the biggest gain or response. For example, if the frequency is too high, the length L may be too small.
According to some embodiments, an on-chip rectangular helix antenna can be designed by the following steps. First, a single round of the rectangular helix antenna is calculated to be one wavelength (λ) in the layer that contains the antenna, e.g., SiO2. Second, due to similar antenna behavior, the length (d) of side electrodes 106, e.g., 10-17 μm, is used as the side length (ds) of a folded dipole antenna design 103 in
The upper electrodes 202 are disposed at an angle (β) with respect to the plurality of lower electrodes 204. However, in other embodiments, the angle can be zero, i.e., the upper electrodes 202 can be parallel to the lower electrodes 204, and the side electrodes 206 can be inclined at an angle to connect each upper electrode 202 and lower electrode 204. The upper electrodes 202, the lower electrodes 204, and the side electrodes 206 form one continuous electrode spiraling around an inner shape of a rectangular bar. It should be noted that MEMS helix antenna does not have to be rectangular, and the inner shape of a bar can be a shape other than rectangular. For example, the bar could be circular, oval, elliptical, or other polygon shapes such as hexagon or octagon.
A ground plane 208 is disposed in a metal layer at the side of the integrated chip 212, which can be perpendicular in some embodiments. In some embodiments, the ground plane 208 has an area at least three times of a rectangular area 209 of the MEMS rectangular helix antenna 200, e.g., 4-5 times. In some embodiments, the lower electrodes 204 are disposed over a passivation layer of the integrated chip 212. The upper electrodes 202 and the lower electrodes 204 comprise metal, e.g., aluminum, copper, any other suitable metal or any combination thereof. A contact pad 210 connects the MEMS rectangular helix antenna 200 to a transmitter or a receiver in the integrated chip 212 or outside. In some embodiments, the side electrodes 206 comprise metal. (In some embodiments, the rectangular helix antenna 200 is contained in an extended waveguide, e.g., comprising a dielectric layer, such as 304 shown in
According to some embodiments, a rectangular helix antenna in an integrated circuit includes upper electrodes disposed in a first metal layer, lower electrodes disposed in a second metal layer, and side electrodes connecting the upper electrodes with the lower electrodes, respectively. The upper electrodes are disposed at an angle with respect to the lower electrodes. The upper electrodes, the lower electrodes, and the side electrodes form one continuous electrode spiraling around an inner shape of a rectangular bar.
According to some embodiments, a micro-electromechanical system (MEMS) helix antenna implemented over an integrated chip includes upper electrodes disposed above the integrated circuit, lower electrodes disposed over the integrated chip, and side electrodes connecting the upper electrodes with the lower electrodes, respectively. The upper electrodes, the lower electrodes, and the side electrodes form one continuous electrode spiraling around an inner shape of a polygonal, circular, or elliptical bar.
A skilled person in the art will appreciate that there can be many embodiment variations of this disclosure. Although the embodiments and their features have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosed embodiments, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure.
The above method embodiment shows exemplary steps, but they are not necessarily required to be performed in the order shown. Steps may be added, replaced, changed order, and/or eliminated as appropriate, in accordance with the spirit and scope of embodiments of the disclosure. Embodiments that combine different claims and/or different embodiments are within scope of the disclosure and will be apparent to those skilled in the art after reviewing this disclosure.
Claims
1. A rectangular helix antenna in an integrated circuit, comprising:
- a plurality of upper electrodes disposed in a first metal layer;
- a plurality of lower electrodes disposed in a second metal layer; and
- a plurality of side electrodes connecting the upper electrodes with the lower electrodes, respectively,
- wherein the upper electrodes are disposed at an angle with respect to the lower electrodes, and the upper electrodes, the lower electrodes and the side electrodes form one continuous electrode spiraling around an inner shape of a rectangular bar.
2. The rectangular helix antenna of claim 1, further comprising a first ground plane disposed in a third metal layer above the first metal layer.
3. The rectangular helix antenna of claim 2, further comprising a second ground plane disposed in a fourth metal layer below the second metal layer.
4. The rectangular helix antenna of claim 3, wherein the first ground plane and the second ground plane are connected by a vertical ground plane to form a folded grounding.
5. The rectangular helix antenna of claim 4, wherein the folded grounding has an area at least three times greater than that of a rectangular area of the rectangular helix antenna.
6. The rectangular helix antenna of claim 1, further comprising an off-chip grounding disposed at a side of the integrated circuit.
7. The rectangular helix antenna of claim 1, wherein the side electrodes comprise vias.
8. The rectangular helix antenna of claim 1, wherein there is at least one metal layer between the first metal layer and the second metal layer.
9. The rectangular helix antenna of claim 1, further comprising an extended waveguide.
10. A micro-electromechanical system (MEMS) helix antenna implemented over an integrated chip, comprising:
- a plurality of upper electrodes disposed above the integrated chip;
- a plurality of lower electrodes disposed over the integrated chip; and
- a plurality of side electrodes connecting the upper electrodes with the lower electrodes, respectively,
- wherein the upper electrodes, the lower electrodes, and the side electrodes form one continuous electrode spiraling around an inner shape of a bar.
11. The MEMS helix antenna of claim 10, further comprising an off-chip grounding disposed at a side of the integrated chip.
12. The MEMS helix antenna of claim 11, wherein the off-chip grounding has an area at least three times greater than that of a rectangular area of the MEMS helix antenna.
13. The MEMS helix antenna of claim 10, wherein the lower electrodes are disposed over a passivation layer of the integrated chip.
14. The MEMS helix antenna of claim 10, further comprising a contact pad connecting the MEMS helix antenna to a transmitter or a receiver in the integrated chip.
15. The MEMS helix antenna of claim 10, wherein the inner shape of the bar is a rectangular, a hexagonal, or an octagonal shape.
16. The MEMS helix antenna of claim 10, wherein the upper electrodes, the lower electrodes, and the side electrodes form one continuous electrode spiraling around an inner shape of a circular, oval, or elliptical bar.
17. The MEMS helix antenna of claim 10, wherein the MEMS helix antenna is contained in a waveguide.
18. The MEMS helix antenna of claim 17, wherein the waveguide comprises a dielectric layer.
19. An integrated chip having a rectangular helix antenna, the rectangular helix antenna comprising:
- a plurality of upper electrodes disposed in a first metal layer;
- a plurality of lower electrodes disposed in a second metal layer;
- a plurality of side electrodes connecting the upper electrodes with the lower electrodes; and
- an off-chip grounding disposed at a side of the integrated chip, wherein the off-chip grounding has an area at least three times of a rectangular area of the rectangular helix antenna,
- wherein the upper electrodes are disposed at an angle with respect to the lower electrodes, and the upper electrodes, the lower electrodes, and the side electrodes form one continuous electrode spiraling around an inner shape of a rectangular bar.
20. The integrated chip of claim 19, wherein the rectangular helix antenna further comprises an extended waveguide.
Type: Application
Filed: Oct 14, 2010
Publication Date: Apr 19, 2012
Patent Grant number: 9209521
Applicant: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD. (Hsinchu)
Inventors: Cheng-Hsien HUNG (Taoyuan City), Yu-Ling LIN (Taipei), Ho-Hsiang CHEN (Hsinchu City)
Application Number: 12/904,692
International Classification: H01Q 1/36 (20060101);